In order to ensure the good lubrication of the supporting parts,it is necessary to design various oil grooves on the shaft or bearing surface.However,increasing the oil grooves will increase the oil leakage and affect the lubrication of other parts.In order to discuss the influence of oil groove structure on the oil leakage of sliding bearing,three kinds of gear sliding bearings with different oil groove structures were proposed.The total leakage of the bearing was divided into two parts,the leakage from the oil groove and the leakage from the clearance,and the leakage from the oil groove was calculated by CFD simulation,the leakage from the clearance was calculated by one-dimensional simulation.Based on the simulation test of a light diesel engine lubrication system,the validity of the calculation method was verified.The results show that the total oil leakage is the least for the sliding bearing without oil groove,that is slightly increased for the sliding bearing with axial oil groove,and that is significantly increased for the sliding bearing with axial and circumferential oil grooves.For light duty engines with low total oil flow rate,the oil groove structure of sliding bearings should be designed reasonably to avoid insufficient oil pressure caused by excessive oil leakage.